The Karst Walking Trail snakes its way through a fascinating region of high biodiversity: this small, intricate network of habitats in the southern Harz is home to a variety of rare and heavily protected species of flora and fauna. However, it is the karst landscape – formed from sulphate rock (gypsum and anhydrite) – that makes the southern Harz region particularly special. These rocks dissolve especially quickly, and are carried away by the water from the karst springs.

The Rhume spring (62 million cubic metres) alone accounts for 40,000 tonnes of gypsum and 17,000 tonnes of limestone leaving the southern Harz every year, along the Weser and into the North Sea. This gives rise to countless deep hollows (10-200m), many of which collapse as they eventually grow too large, forming sinkholes on the surface. The result is a varied and unusual landscape that everyone can enjoy on the karst walking trail. Highlights include Heimkehle Cave and Barbarossa’s Cave, the Juessee lake and ‘Swimming Island’ sinkholes and the moor landscape of Teufelsbäder (’devil’s baths’). Disappearing rivers and streams such as those in the Bauerngraben nature reserve or the Sieber river are typical of karst landscapes, as are the many gypsum cliffs.

Tip: Heimkehle show cave

At two kilometres in length, the Heimkehle cave is one of the biggest in the southern Harz and 700 metres of it are open to the public. In winter, the cave is home to many bats, and in August and September you can often see them flying around.

At a glance:

Starts/Ends: Pölsfeld (near Sangerhausen)

Length: 233km

Number of stages: 6

Altitude variation: the route runs at an altitude of between 170m and max. 290m above sea level